Many drivers such as camellia, cast5, etc are using ECB macro.
ECB macro internally calls kernel_fpu_begin() then calls encrypt()
and decrypt() and then it calls kernel_fpu_end().
If too many blocks are given, it acquires fpu context for too long.
kernel_fpu_{begin | end}() internally calls preempt_{disable | enable}().
So, RCU stall would occur because of too long FPU context
period.
The purpose of this is to not exceed 4096 bytes to encrypt() and
decrypt() in an FPU context.
Fixes: 827ee47228a6 ("crypto: x86 - add some helper macros for ECB and CBC modes")
Suggested-by: Elliott, Robert (Servers) <elliott@xxxxxxx>
Signed-off-by: Taehee Yoo <ap420073@xxxxxxxxx>
---
arch/x86/crypto/ecb_cbc_helpers.h | 34 ++++++++++++++++++++++++-------
1 file changed, 27 insertions(+), 7 deletions(-)
diff --git a/arch/x86/crypto/ecb_cbc_helpers.h b/arch/x86/crypto/ecb_cbc_helpers.h
index eaa15c7b29d6..551d8bdfd037 100644
--- a/arch/x86/crypto/ecb_cbc_helpers.h
+++ b/arch/x86/crypto/ecb_cbc_helpers.h
@@ -11,19 +11,35 @@
* having to rely on indirect calls and retpolines.
*/
+#define ECB_CBC_WALK_MAX 4096
+
#define ECB_WALK_START(req, bsize, fpu_blocks) do { \
void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req)); \
+ unsigned int walked_bytes = 0; \
const int __bsize = (bsize); \
struct skcipher_walk walk; \
- int err = skcipher_walk_virt(&walk, (req), false); \
+ int err; \
+ \
+ err = skcipher_walk_virt(&walk, (req), false); \
while (walk.nbytes > 0) { \
- unsigned int nbytes = walk.nbytes; \
- bool do_fpu = (fpu_blocks) != -1 && \
- nbytes >= (fpu_blocks) * __bsize; \
const u8 *src = walk.src.virt.addr; \
- u8 *dst = walk.dst.virt.addr; \
u8 __maybe_unused buf[(bsize)]; \
- if (do_fpu) kernel_fpu_begin()
+ u8 *dst = walk.dst.virt.addr; \
+ unsigned int nbytes; \
+ bool do_fpu; \
+ \
+ if (walk.nbytes - walked_bytes > ECB_CBC_WALK_MAX) { \
+ nbytes = ECB_CBC_WALK_MAX; \
+ walked_bytes += ECB_CBC_WALK_MAX; \
+ } else { \
+ nbytes = walk.nbytes - walked_bytes; \
+ walked_bytes = walk.nbytes; \
+ } \
+ \
+ do_fpu = (fpu_blocks) != -1 && \
+ nbytes >= (fpu_blocks) * __bsize; \
+ if (do_fpu) \
+ kernel_fpu_begin()
#define CBC_WALK_START(req, bsize, fpu_blocks) \
ECB_WALK_START(req, bsize, fpu_blocks)
@@ -65,8 +81,12 @@
} while (0)
#define ECB_WALK_END() \
- if (do_fpu) kernel_fpu_end(); \
+ if (do_fpu) \
+ kernel_fpu_end(); \
+ if (walked_bytes < walk.nbytes) \
+ continue; \
err = skcipher_walk_done(&walk, nbytes); \
+ walked_bytes = 0; \
} \
return err; \
} while (0)
--
2.17.1
